Transformer



March 8, 1927.

L. H. BURNHAM TRANSFORMER Filed April 14, 1925 Fig. I.

lnventok-z Locke H.13urnham,

H is Attorney.

FLg. 3.

Patented Ma -.8, i

UNITED STATES LOGKE H. BURNHAM, F PITTSFIELD, MASSACHUSETTS, ASS IGNOR TO ELECTRIC COMPANY, A CORPORATION OF NEW Y ORK.

; ftszoasi PATENT OFFICE} TRANSFORMER.

' Application filed April 14, 1925. Serial No. 23,118

My oinvention relates to transformers of the oil immersed water cooled type. The maximum capacity of a transformer is limited by the temperature of its windings and core while under load and various arrangements have been proposed and used to increase the capacity by increasing the rate at which the heat generated in the transformer is dissipated therefrom. In the case of oil immersed transformers, this result is commonly attained by providing pipe coilsimmersed in the oil and circulating a cooling current of water through the plpe coils to absorb andcarry away heat transferred by theoil from the transformer to the pipe coils. While an oil immersed transformer is under load, the. oil in the upper part of the casing is warmer than that in the lower part of the casing because the oil rises by convection as it is heated by the transformer.- For efficient transfer and dissipation of heat from the transformer, it is therefore desirable that the transformer be located in the cool oil in the lower part of the casing and that the cooling-pipe coils be located in the Warm or hot oil in the upper part of the casing. It is also desirable that the pipe coils be so located as to leave a free and unobstructed opening for convenient removal of the transformer from the casing after the cover of the casing has been removed. It is still further desirable that the in connection with the accompanying'drawing in which Fig.1 shows an oil immersed transformer having a. two part casing and cooling pipecoils arranged in accordance with the invention; Fig. 2 shows-the lower section of the casing as it may be used, to enclose and protect the transformer during shipment; Fig. 3 shows the upper section of the casing; and Fig. 4 is a vertical sectional detail showing the arrangement of the cooling pipe coils.

7 Like reference characte s refer to similar parts in the different figures of the draw- The'invention is shown in the drawing in connection with' a transformer 10 enclosed in a casing 11 adapted to be' com-- pletely filled with oil inwhich the trans former is immersed. An expansion chamber 12 is provided to vpermit expansion and contraction of the .oil under the influence of temperature changes. A pressure relief pipe 13 with a rupturable diaphragm 14 serves to prevent excessive pressure within the casing 11.

The casing comprises a lower portion or section 15 and an 11 per portion or section 16. The lower section 15 of the casing is,

preferably of about the same height as that of the transformer and its horizontal dimensions as small as "may be and still accommodate the transformer conveniently. The upper section 16 of the casing is larger all around and extends beyond or overhangs the lower section 15 as indicated in Figs. 1 and 4] The upper edge of the lower section 15 'of the casing is rovided with a 'wide flange 17 the outer e ge of this flange being connected to the lower edge of the upper section 16 by a tight but separable joint. A cover 18 closes the top of the casing.

i The overhang, of the upper section 16 ofthe casing provides a convenient s'pace above the wide flange 17 for pipe coils '19 through which a flow of cool water maybe maintained 'to cool the oil in whicli the trans-j former is immersed. By locating'the cooling pipe coils 19 in this space, they 'are'com, centrated near the top of the bodjjofoil where its temperature is highest and there-f fore where the transfer of heat from the oilto the coils will be most rapid and-eflicient.

This disposition of the pipe coils further leaves a free central space large enough to .permit the transformer to be removed from the casing and replaced through this space coils 19 are concentrated in a position high .enough upin the casing so that they do not which there is at present an in creasingde mand, it is sometimes found that a casing is needed which is so tall as-to exceed permis- I sible shipping dimensionsdue to railroad clearances and the construction which has been described is well adapted to meet this condition. The joint at the outer edge of the flangel? is similar to the joint at the edge of the cover 18 so that by removing the upper section 16 of the casing as shown in Fig. 3, the cover 18 may be used to close the'lower section 15 containing the transformer as shown in Fig. 2. The shipping height is thus substantially reduced. Any small openings in the cover such as those necessary for the bushings, pressure relief pipe and the connection to the expansion chamber, may be closed by small temporary plates to protect the transformer and to permit it to be shipped completely immersed in oil. The upper section l6'of thecasing may be used to enclose and protect the cooling pipe coils 19 during shipment; What I claim as newand desire to secure by Letters Patent of the United States is:

1. The combination of a transformer with a casing adapted to contain a body of oil for immersion of the transformer, said casing comprising a lower portion containing said transformer and an upper portion overhanging the lower portion, and cooling pipe coils in'the overhanging part of said upper portion, said coils surrounding a central space of sufficient size to permit removal there through of said transformer without disturbing said coils, said lower casing section being connected to said upper sectionby a separable joint and having its upper edge arranged to fit and receive a cover, whereby said lower section, a flange between said two sections andconnected to the lower edge, of the upper section by a separable joint, a cover closing the top of said upper section, the outer edge of said flange being arranged to fit and receive said cover, whereby said cover may close the complete casing with the two sections assembled or the lower section with the upper section removed, and cooling pipe coils disposed in the overhanging space in said upper section.

3. The combination of a transformer with a casing, said casing comprising an upper section and a lower section and adapted to contain a body of oil for immersion of the transformer, the upper section of the casing being larger horizontally than the lower section to provide therein a space overhanging said lower section, a flange-between said two sections and connected to the lower edge of the upper section by a separable joint, a cover closing the top of said upper section, the outer edge of said flange being arranged to fit and receive said cover, whereby said cover may close the complete casing with the two sections, assembled or the lower section with the upper section removed, and cooling pipe coils disposed in the overhanging space in said upper section, said coils surrounding a central space of suificlent size to permit removal therethrough of said transformer without disturbing said coils.

I In witness whereof, I have hereunto set my hand this 8th day of April 1925.

LOCKE H. BURNHAM. 

